main.css

body,
body * {
    margin: 0;
    padding: 0;
    vertical-align: top;
    box-sizing: border-box;
}

body {
    font-family: 'Gill Sans', 'Gill Sans MT', Calibri, 'Trebuchet MS', sans-serif;
}

.main {
    display: flex;
    align-items: center;
    justify-content: center;
    height: 100vh;
    background-color: yellow;
}

.container {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    width: 30rem;
    height: 15rem;
    gap: 2rem;
    background-color: yellowgreen;
    border-radius: 1rem;
}

.inputText {
    border: none;
    background-color: transparent;
    padding: 0.7rem 1.8rem;
    width: 70%;
    border-bottom: 2px solid blue;
    outline: none;
}

.btn {
    padding: 0.6rem 1rem;
    border: none;
    border-radius: 5px;
    background-color: red;
    color: white;
    font-size: 1rem;
    font-weight: bold;
    cursor: pointer;
}

.results {
    font-size: 2rem;
    font-weight: 700;
    color: royalblue;
    overflow: auto;
    width: 25rem;
}